The field of the invention is stabilizers for molded and unshaped plastics and the invention is particularly concerned with the use of a low molecular weight 1,3-butadiene polymer containing an amino group as such a stabilizer for molded and unshaped plastics.
The state of the art of stabilizers for plastics may be ascertained by reference to U.S. Pat. Nos. 3,627,775; 4,110,334; and 4,170,588, the disclosures of which are incorporated by reference herein.
The 1,3-polybutadienes containing epoxy groups and useful in the present invention are prepared as disclosed in U.S. Pat. Nos. 3,329,734; 3,321,541; 3,312,752; 3,341,617; 3,428,699; 3,789,090; 3,852,373; 3,983,183; and 4,269,626, the disclosures of which are incorporated by reference herein.
The state of the art of the additives useful in the present invention may be ascertained by reference to the Kirk-Othmer, "Encyclopedia of Chemical Technology", 2nd Edition, Volume 16 (1968) pp. 92-95, particularly the heat and light stabilizers disclosed at page 93, the disclosure of which is incorporated by reference herein.
It is known that derivatives of sterically inhibited piperidine derivatives, in particular of 2,2,6,6-tetramethylpiperidine, are useful as light stabilizers. For instance, U.S. Pat. No. 3,627,775 discloses the alkylpiperidylesters of dicarboxylic acids, and U.S. Pat. No. 4,110,334 discloses the tetramethyl-diaza-oxa-oxo-dispiroalkanes. U.S. Pat. No. 4,170,588 discloses 1,3-bis-alkylamino-cyclobutenediylium-2,5-diolates as stabilizers for plastics. However, these mostly low molecular weight piperidine derivatives are frequently too volatile or too easily extracted, or they evince excessive migration tendencies.
The higher molecular weight and especially polymeric derivatives of sterically inhibited piperidine derivatives which have become known, however, incur the drawback when considered as light stabilizers for plastics in that they are either inadequately effective in or incompatible with the plastic that is meant to receive them.
According to the prior art, there is a problem in preparing higher molecular weight, in particular polymeric tetramethylpiperidine derivatives which are quite compatible with plastics and also stabilize them well. The stabilizing effect should be permanent, that is, the stabilizers should not be volatile in practical use, nor permit extraction, nor evince any migration tendency. The stabilizers of the present invention are especially good light stabilizers.